A roller harrow is typical of an agricultural implement such as that referred to in the "Abstract" hereof. The purpose of the pivotable or floating hitch member in operating or lowered mode is to enable the implement to follow the ground contour. It is desirable to lock out this pivotal movement in the transport mode of the implement so as to afford better control of the trailing implement over roads and highways and to eliminate teetering of the frame. The usual implement of this type is carried on wheel structure including a cranked axle or other frame-to-axle structure capable of being operated, as by hydraulic power, to selectively raise or lower the frame between its two modes or positions. The present invention provides linkage between the cranked axle or equivalent means and the hitch member for achieving the desired hitch member status in each mode; that is, a pivotable hitch member during ground working and a rigid hitch member during transport.
The invention features simple and positive linkage that may be easily incorporated into existing implements. Also a linkage that involves simple and efficient means for adjusting the hitch member as to height. The linkage employs a hitch member control member pivotable on the frame adjacent to the hitch member, plus a connection between this member and the drawbar. A link connected between the cranked axle or raising and lowering means is operative to determine the status of the hitch-connected member by means of a stop or abutment which frees the member and hitch member when the implement is in working position but which abuts the member and thus holds the hitch member fixed when the implement is raised. These and further features and significant advantages will appear to those versed in the art as a preferred embodiment of the invention is disclosed in the ensuing description taken in conjunction with the accompanying drawings.